Apparatus for use in coal washing tanks



Jan. 15, 1963 L. scHANNE 3,073,450

APPARATUS FOR USE 1N coAL WASHING TANKS Filed June i9, 1959 3,073,450APPARATUS FOR USE IN COAL WASHING TANKS Lothar Schanne, Elversberg(Saar), Saarland, Germany,

assigner to Saarbergwerke Aktiengesellschaft, Saarbrncken, Saarland,Germany, a company of Germany Filed .lune 19, 1959, Ser. No. 821,513Claims priority, application France Oct. 9, 1958 12 Claims. (Cl.209-455) This invention relates to improvements in apparatus for use incoal washing tanks for the separation of coal and shale in which thecoal and shale are to be immersed in water and separated by theirdifference in density, the shale being heavier than the coal.

Coal washing tanks are usually provided with means for automaticallyregulating the discharge of the coal and shale and this regulation isachieved by means of a oat which is vertically displaceable to modifycertain operating conditions of the tank. Where compressed air isutilized to impart a pulsatory motion to the water in the tank the floatusually is arranged to control the amplitude of the pulsations impartedto the water. The float is arranged to be displaced in response tovariations in the thickness of the shale layer in the tank and is soarranged that when this thickness increases, due either to feeding alarger quantity of material to the tank or to a higher proportion ofshale being present in the raw material, the float rises and causes moreintensive pulsations to be imparted to the water. Conversely, areduction in the thickness of the shale layer causes the float todescend and results in a decrease in the amplitude of the pulsationsimparted to thewater.

The amplitude of the pulsations imparted to the water is controlledeither by controlling the supply of cornpressed air to a compressed airchamber or by controlling the escape of compressed air from thecompressed air chamber, such control being effected in response tdisplacement of the piston through a piston and cylinder arrangementwhich transmits the movement of the float to suitable means controllingeither the supply of compressed air to the chamber or the escape ofcompressed air from the chamber.

Many experiments have shown that, where the amplitude of the pulsationsis controlled by controlling the supply of compressed air to thechamber, the apparatus does not respond accurately to small variationsin the depth or thickness of the shale layer. Furthermore, where theamplitude of the pulsations is controlled by controlling' the escape ordischarge of compressed air from the chamber, the apparatus onlyoperates satisfactorily within narrow limits of variations in the depthor thickness of the shale layer and is unsatisfactory when thesevariations exceed such limits.

It is an object of the present invention to provide an improvedapparatus for use in coal washing tanks for the separation of coal andshale which shall not be subject to the disadvantages referred to above,

Apparatus for use in a coal washing tank for the separation of coal andshale in which the coal and shale are to be immersed in water comprisesmeans operable under the influence of compressed air supplied to achamber to impart pulsations to the water, means displaceable inaccordance with the thickness of the shale layer, first means responsiveto displacement of the displaceable means to control the discharge ofair from said chamber and second means responsive to displacement of thedisplaceable means outside predetermined limits to control the supply ofcompressed air to said chamber.

One embodiment of the present invention will now be described by Way ofexample, reference being made to the accompanying drawings in which:

FIG. l is a diagrammatic sectional view of part of a States Patent OPatented Jan. 15, 1963 ICC coal washing tank provided with mechanicalmeans in the form of a piston for imparting pulsatory movements to theliquid in the tank, and

FIG. 2 is a diagrammatic view on a larger scale of a regulating orcontrolling device for a coal washing tank which is provided with meansfor admitting compressed air to produce pulsatory movements of theliquid in the tank.

The coal washing tank illustrated in FIG. l is divided by a centralseparating wall 1a into two compartments 1b and 1c which communicatewith each other at their lower ends below the separating wall 1a. Wateris disposed in the tank and a piston 2 is slidably disposed in` thecompartment 1c and has a pulsatory motion imparted to it in knownmanner, the piston 2 communicating its pulsations to the water in thetank. The pulsatory motion may be imparted to the water in the tank bycompressed air introduced into a chamber A located above the compartment1c.

The material to be separated is supplied to the compartment 1b, ltheheavier shale 3 falling on to a grating 4 whilst the pieces of coal 3a.are supported on the shale layer. A oat 5 (FIG. 2) rests on the shalelayer and is carried on the lower end of a rod 6 slidable vertically ina guide 7. The upper end of the rod 6 is articulated at 8 to a rod 9which is itself articulated at 10 to the shaft 1,1 of a slide valve 12of known type. The slide valve 12 contains two piston-type valve members13 and 14 which are secured on the shaft 11, `and it receives -uid underpressure yfrom a pipe 15a opening into the valve between the twopiston-type valve members 13 and 14. Two interconnected pipes 15b and15e` open one int-o each end of the valve 12 yfor the purpose ofdischarging fluid therefrom. Two outlet pipes 16 and 18 extend from thevalve 12 respectively to the upper end of a cylinder 17 4and the lowerend thereof, the outlet pipes 16 and 18 opening into the valve 12 atsuch locations as to be normally closed by the piston-type valve membersy13 and 14 respectively when the shaft 11 is in its normal position andin such manner that displacement of the shaft 11 in one direction placesthe outlet pipe 16 in communication with fluid from the pipe 15a whilstthe outlet pipe 18 is placed in communication with the discharge pipe15C and displacement of the shaft 11 in the opposite direction vplacesthe `outlet pipe 18 in communication with huid .from the pipe 15a'whilst the outlet pipe 16 is placed in communication with the dischargepipe 15b. A piston 19 is displaceable in the cylinder 17 and is mountedon a rod 20 which carries at its lower end a valve member 21 adapted tobear against a seat 22 surrounding an outlet orice 23 in the chamber A,through which oritice the compressed -air in the chamber can escape orbe discharged.

The rod 20 is articulated at 24 to a rod 25 which itself is articulatedto a triangular plate 26 pivotally carried at one corner lon 1a xed pin27. A second corner of the plate 26 is articulated to la rod 29 carryinga stud 30 at its end.

The stud 30 is :displaceable in a groove 31 formed in a disc 32 carriedon the exterior of a pipe 33 through which compressed air is admitted tothe chamber A. The longitudinal walls `defining the groove 31 conform toarcs of circles concentric about the axis of a pin 34 secured centrallyof the disc 32 and extending through the pipe 33 normal to the axisthereof. The pin 34 is rotatable -about its axis, suitable bearingsurfaces being provided in the wall of the pipe 33, and carries acircular butterfly valve 35 disposed within the pipe 33 and having adiameter substantially equal to the internal diameter of the pipe 33V soas to be capable of substantially closing the latter, the butterflyvalve 35 being secured to the pin 34 substantially along a diameter. Theplane of the )butterfly valve is sub-v` stantially normal to that of thedisc 32 and rotation of the latter produces a corresponding rotation ofthe former.

The pin 34 further carries a pointer 36 extending normal to its axis andmovable over a scale 37 substending an angle of 90 to the `axis of thepin 34 and bearing graduations from to 1, the pointer 36 being arrangedto indicate the graduation 0 when the pipe 33 is closed by the butterflyvalve 35 and the graduation l when the pipe 33 is Wholly open.

The disc 32 is formed with a second groove 38 the longitudinal walls ofwhich conform to arcs of circles concentric about the `axis of the pin34. A stud 39 is displaceable in the groove 3S and is carried on arestoring spring 40 secured by its lower end 41 to the pipe 33.

The operation of the apparatus will now be described:

When the thickness of the shale layer 3 increases, such an increasebeing due either to an increase in the quantity of material supplied tothe tank or to the material containing a larger quantity of shale, thefloat 5 rises moving the rod 6 upwardly and displacing the shaft 11 ofthe slide valve 12 to the right in FIG. 2 towards the position indicatedin dotted lines. Thus the pipe 16 is uncovered and fluid under pressurefrom the pipe 15a is conveyed through the pipe 16 to the upper end ofthe cylinder 17 causing the downward displacement of the piston 19. Thedownward :displacement of the piston 19 causes a corresponding downwarddisplacement of the valve member 21 towards its seat 22 and reduces theescape of air through the orifice 23. Simultaneously, the downwarddisplacement of the piston 19 pivots the triangular plate 26 about thepin 27 and through the rod 29 displaces the stud 30 in the groove 31without rotating the disc 32.

Thus, if the thickness of the shale layer 3 increases slightly, a firstregulating effect is obtained by reducing the escape of compressed lairfrom the chamber A and thereby increasing the amplitude of thepulsations imparted to the water in the tank to reduce the thickness ofthe shale layer.

If the thickness of the shale l-ayer 3 continues to increase the float 5rises correspondingly and the orifice 23 is closed more and more lby thevalve member 21 whilst the stud 30 continues to lbe displaced towardsthe lower end of the groove 31 until a stage is reached when the stud 30engages the lower end of the groove 31 4and further displacement of thestud 30 produces a corresponding rotation of the disc 32 and of thebuttery valve 35 in the sense to increase the supply of compressed airto the chamber A. Movement of the disc 32 is opposed by the spring 40and is communicated to the pointer 36 which is moved towards thegraduation 1.

Thus an increase in the thickness of the shale layer 3 beyond apredetermined limit brings a second regulating effect into operation byincreasing to admission of compressed air to the chamber A whilstreducing the escape of compressed air therefrom thereby greatlyincreasing the amplitude of the pulsations imparted to the water. Thethickness of the shale layer is accordingly reduced until a value isreached when the butterfly valve 35 appreaches its normal or meanposition under the influence of the spring 40, in which position thepointer 36 indicates the graduation 1/2 on the scale 37.

Conversely a slight reduction in the thickness of the shale layer 3causes the float 5 and the rod 6 to descend, the shaft 11 then beingdisplaced to the left in FIG. 2 thereby causing fluid under pressure tobe fed from the pipe 15a to the lower end of the cylinder 17 through thepipe 18. This causes the piston 19 to rise and lifts the valve member 21away from its seat 22 to increase the amount of air escaping from thechamber A through the orifice 23 and thereby reducing the amplitude ofthe pulsations imparted to the water and Vhence increasing the thicknessof the shale layer.

lf the thickness of the shale layer decreases below a predeterminedlimit, the corresponding motion of the piston 19 causes the plate 26 torotate to the extent that the stud 3) engages the upper end of thegroove 31 and rotates the disc 32 and the butterfly valve 3S in thecounter-clockwise direction to tend to close the passage through thepipe 33. Simultaneously the pointer 36 moves towards the graduation 0.Such rotation of the butterfly valve 35 reduces the supply of compressedair to the chamber A Whilst the escape therefrom is increased by thelifting of the valve member 21 and this results in a considerablereduction in the amplitude of the pulsations imparted to the water andhence an increase in the thickness of the shale layer up to apredetermined value corresponding to normal operation of the tank.

It will be understood that, as the float 5 is itself subjected to thepulsatory movement of the water, the pistons 13 and 14 are arranged notto be displaced due to slight variations of the float corresponding tonormal pulsatory movement or they are so dimensioned as not to uncoverthe pipes 16 and 18 unless the motion imparted to the shaft 11 isgreater than that normally imparted thereto due to the pulsatorymovement of the water.

It will be appreciated that the disc 32 may be formed with a pluralityof concentric grooves corresponding to the groove 31 but each of adifferent length than the other so that the degree of movement permittedto the piston 19 before the valve 3S is operated may be selected byengaging the stud 30 in the appropriate one of such grooves.

What I claim is:

1. Apparatus for use in a coal washing tank for the separation of coaland shale in which the coal and shale are to be immersed in water, saidapparatus comprising, in combination, a chamber having a dischargeorice, means for admitting compressed air to the chamber so that thecompressed air admitted to said chamber may impart pulsations to thewater, means displaceable in response to changes in the thickness of theshale layer, first means responsive to displacements of saiddisplaceable mean for controlling the discharge of air through saidorifice, and second means responsive to displacements of saiddisplaceable means beyond a predetermined upper limit and below apredetermined lower limit for controlling the admission of compressedair to said chamber.

2. Apparatus according to claim l wherein said rst means comprises avalve member movable towards and away from said orifice for varying thedischarge of air from said chamber in accordance with the displacementof the displaceable means.

3. Apparatus according to claim 2, further comprising a cylinder, apiston operatively connected with said displaceable means anddisplaceable in the cylinder in response to the displacement of thedisplaceable means, and a connection between said piston and said valvemember.

4. Apparatus according to claim 3, wherein the operative connectionbetween said piston and said displaceable means comprises a slide valveoperatively connected to the displaceable means for controlling the flowof a compressed fluid to said cylinder and for thereby controlling thedisplacements of said piston in the cylinder.

5. Apparatus for use in a coal washing tank for the separation of coaland shale in which the coal and shale are to be immersed in water, saidapparatus comprising, in combination, a chamber having a dischargeorifice, means comprising a pipe for admitting compressed air to saidchamber so that the compressed air may impart pulsations to the water,means displaceable in accordance with the thickness of the shale layer,means responsive to the displacement of the displaceable means forcontrolling the discharge of air through said orifice, and a valvedisposed in said pipe and operatively connected with said displaceablemeans, said valve responsive to displacement of the displaceable meansbeyond a predetermined limit for controlling the supply of compressedair to said chamber.

6. Apparatus according to claim wherein the operative connection betweensaid displaceable means and said valve comprises linkage meansincorporating a lost motion connection.

7. Apparatus for use in a coal Washing tank for the separation of coaland shale in which the coal and shale are to be immersed in Water, said.apparatus comprising, in combination, a chamber having a dischargeorifice, a pipe connected to the chamber for admitting compressed Aairthereto so that the compressed air admitted to said chamber may impartpulsations to the water, means dis placeable in accordance with thethickness of the shale layer, a cylinder, a piston displaceable in thecylinder in accordance with thesupply of pressure iuid to the endsthereof, a slide valve operatively connected with and responsive todisplacement of said displaceable means for controlling the supply of apressure fluid to the cylinder and for thereby displacing said piston inresponse to displacements of said displaceable means, a valve memberconnected to said piston and movable towards and away from saiddischarge orice for controlling the discharge of air therefrom inresponse to displacements of said`displaceable means, a valve disposedin said pipe for controlling the admission of compressed air to saidchamber, and a lost motion connection between said valve and saidpiston.

8. Apparatus according to claim 7 wherein said lost motion connectioncomprises an element connected to said valve and having a groove formedtherein, linkage means connected with said piston, and a stud connectedwith said linkage means and shiftably received in said groove.

9. Apparatus according to claim 8 vwherein said element is a disccomprising a pin rotatably mounted in said pipe and connected with saidvalve, said pin rotating said valve when said stud engages an end of thegroove in said disc.

l0. Apparatus according to claim 9 wherein the longitudinal walls ofsaid disc dening said groove conform to arcs of circles concentric aboutthe axis of the pin.

l1. Apparatus according to claim 8 wherein said element is formed with asecond groove and further comprising a stud displaceably received insaid second groove and a restoring spring connected with said pipe andsaid stud.

l2. Apparatus for use in a coal washing tank for the separation of coaland shale in which the coal and shale are to be immersed in water, saidapparatus comprising, in combination, a chamber having a dischargeorifice, a pipe connected to said chamber for admitting compressed airthereto so that the compressed air may impart pulsating movements to thewater, means displaceable in response to changes in the thickness of theshale layer, a cylinder, a piston displaceable in said cylinder inaccordance with changes in the supply of a pressure huid to the ends ofsaid cylinder, a slide valve responsive to displacement of saiddisplaceable means for controlling the supply of pressure iiuid to saidcylinder, a valve member operatively connected 4to said piston andmovable towards and away from said discharge orifice in accordance withthe displacement of said vpiston to thereby control the discharge ofcompressed air from said chamber in response to displacements of saiddisplaceable means, a circular buttery valve disposed in said pipe forcontrolling the admission of compressed air to said chamber, a pinsecured to and extending along a diameter of said butterily valve, saidbutterfly valve rotatable with saidv pin, a disc formed with a grooveand connected for rotation with said pin externally of said pipe, a studdisplaceably received in said groove, and linkage means connecting saidstud to said piston whereby a displacement of the piston beyond apredetermined limit displaces said stud into engagement with an end ofsaid groove to rotate said butterfly valve and to thereby control theadmission of compressed air to said chamber in response to displacementsof said displaceable means.

References Cited in the tile of this patent UNITED STATES PATENTS2,035,750 Hirst Mar. 31, 1936 2,169,544 Vissac Aug. l5, 1939 2,177,537Sloan Oct. 24, 1939 2,828,015 Vissac Mar. 25, 1958 2,889,045 Turpin June2, 1959

1. APPARATUS FOR USE IN A COAL WASHING TANK FOR THE SEPARATION OF COALAND SHALE IN WHICH THE COAL AND SHALE ARE TO BE IMMERSED IN WATER, SAIDAPPARATUS COMPRISING, IN COMBINATION, A CHAMBER HAVING A DISCHARGEORIFICE, MEANS FOR ADMITTING COMPRESSED AIR TO THE CHAMBER SO THAT THECOMPRESSED AIR ADMITTED TO SAID CHAMBER MAY IMPART PULSATIONS TO THEWATER, MEANS DISPLACEABLE IN RESPONSE TO CHANGES IN THE THICKNESS OF THESHALE LAYER, FIRST MEANS RESPONSIVE TO DISPLACEMENTS OF SAIDDISPLACEABLE MEAN FOR CONTROLLING THE DISCHARGE OF AIR THROUGH SAIDORIFICE, AND SECOND MEANS RESPONSIVE TO DISPLACEMENTS OF SAIDDISPLACEABLE MEANS BEYOND A PREDETERMINED UPPER LIMIT AND BELOW APREDETERMINED LOWER LIMIT FOR CONTROLLING THE ADMISSION OF COMPRESSEDAIR TO SAID CHAMBER.